PSLE Science: How to Answer Open-Ended Questions

13 October 2026 · Tutor Circle

Many children lose PSLE Science marks on the sentence, after they have understood the topic. The open-ended questions, the ones in Booklet B, ask the pupil to apply a concept to a diagram or a set of results. A keyword in the wrong sentence does not collect the mark. A plain sentence that shows the concept does.

A boy in school uniform and a woman looking closely at a glass of water covered in droplets — The mark goes to the concept applied to this question. A loose keyword, on its own, does not.

Where the marks slip: Booklet B, the open-ended or structured questions
What markers credit: The concept, applied to this question. A loose keyword is not enough
State / name: The fact. Usually one mark. Stop there
Explain / why: Concept, plus the evidence in the question, plus the link
A common swap: Heat and temperature, evaporation and condensation, pollination and fertilisation
Source: SEAB standardisation, as described by the PSLE Science chief marker

What actually earns the mark

A glass of cold water covered in condensation beside a blank notebook on a wooden table — Water on the outside of a cold glass is condensation. Name the concept, then tie it to what the question shows.

After the paper, markers do not invent a private scheme. SEAB holds a standardisation meeting. Acceptable answers and answers that miss the concept are agreed there, and markers then specialise in a few questions each. The Science chief marker has been public about the aim: honour a response that shows understanding, including wording the marker had not listed in advance, and withhold the mark when a keyword is present and the science is not. [1]

That is why a highlighter list of “must-write words” disappoints. The word has to be the right concept for the question. Everything tested sits in the primary science syllabus. If the child cannot name the topic the diagram is about, more keywords will not help. [2]

An explain answer is these three parts in a sentence. Writing the labels “claim” and “evidence” on the script does not add a mark.

Read the command word

A child holding a bar magnet near a pile of paperclips on a wooden table — The command word decides the job. Explain, state, and compare do not ask for the same sentence.

Table 1. What the first word of the question is asking for. Mark counts vary by question. The split below is the usual pattern teachers use when training pupils.
Command	What to write	A mistake that costs the mark
State, name, identify, list	The fact, and stop	A paragraph that never lands on the fact
Describe	What happens, in order, using the diagram	A definition copied from notes, with no reference to the set-up
Explain, why, give a reason	Concept + evidence + link	The concept named, and the “because” missing
Compare	Both sides, on the same point	Two separate descriptions that never meet
Predict	What happens next, tied to the concept already used	A guess with no science attached

Underline the command word before writing. A child who explains a “state” question is slow. A child who states an “explain” question is under-marked. Both can know the topic.

A sentence that holds together

A child's hand drawing arrows between three empty boxes on blank paper — A mark-earning answer links the concept to the evidence in the question, then to what happens.

One worked pattern

Question shape: a beaker of water is left by the window, the water level falls, and the question asks why. A weak answer is “evaporation”. A complete answer is: “The water gained heat from the surroundings and evaporated, so liquid water changed into water vapour and the level fell.” The concept is evaporation. The evidence is the lower level. The link is the change of state. If the question had been about water droplets on the outside of a cold glass, the concept would be condensation, and “evaporation” would be the wrong word used confidently.

Read the question once for the topic, and once for the command word.
Write the concept in the first clause.
Use a number, a label or a difference that appears in the question, so the answer is about this set-up.
Stop when the marks are covered. Two marks need the link. They do not need a second topic.

Words that carry each topic

A primary pupil comparing a plant in sunlight with a plant in shade, talking to a parent — Each topic has a few words the marker is listening for. A correct idea in everyday language can still miss the mark.

These are syllabus words. They earn marks when they are the concept the question is testing. They lose marks when they are swapped with the neighbour in the same row.

Table 2. Pairs pupils swap, and the word that has to match the question. This is a practice list, not a marking scheme.
Topic	Use this when it is the concept	The neighbour pupils write instead
Heat	Heat is gained or lost; a conductor lets heat pass quickly	Temperature, as if it were the same thing
Water cycle	Evaporation needs heat. Condensation is water vapour cooling into liquid	The other process
Plants	Pollination moves pollen. Fertilisation is the fusion that leads to a seed	Either word for both steps
Body	Breathing moves air. Respiration releases energy in cells	“Breathing” as the answer to an energy question
Electricity	A closed circuit, a conductor, series or parallel as the question draws it	“Electricity can flow” with no path
Forces	Gravity, friction, and whether the force speeds the object, slows it, or changes direction	“It moved” with no force named

Where a typical open-ended mark is decided

Concept named

Start

Evidence used

Needed

Link written

The mark

A teaching picture, not an official mark allocation. On an explain question, naming the concept is the start. The mark that separates a 1 from a 2 is the link to the evidence in the question.

What to practise at home

A primary school girl pointing at a potted plant while explaining it to a woman at the table — The useful practice is the child saying the idea out loud, then writing the sentence that uses it.

Take one Booklet B question. Ask the child to point at the sentence in their answer that contains the “because”. If they cannot, the answer is a label. Rewrite that one sentence together, then stop. Ten questions rewritten this way teach more than a stack of unread model answers.

Parents hit a wall here, because the acceptable range is wider than the answer key in a workbook and narrower than “any science word”. A tutor who has marked this paper can say which sentence would pass standardisation. That is a different job from reteaching the whole theme. P5 and P6 rates are on the rate table, and the choice between an ex-MOE teacher and a full-time tutor is on the tutor types page.

Request a P5 or P6 science tutor

Questions parents ask

Do PSLE Science markers only look for keywords?

No. SEAB’s chief marker has said the scheme is built around whether the pupil shows the concept in that question, and that a keyword dropped into the wrong explanation does not earn the mark. Precise words still help, because they are the short way to show the concept. A child who writes “evaporation” for a question about condensation has used a keyword and missed the science.

What is the difference between “state” and “explain” in PSLE Science?

“State”, “name” or “identify” wants the fact, usually one mark, with no story. “Explain”, “why” or “give a reason” wants the concept applied to the diagram or the data, usually two or more marks. A one-word answer on an explain question leaves the second mark on the table. A paragraph on a state question wastes time and can wander off the fact.

How should my child structure an explain answer?

Three moves, in one or two sentences. Name the concept. Point at the evidence in the question, such as the higher temperature or the missing wire. Then link them: because of that evidence, this is what happens. Schools sometimes call this claim, evidence and reasoning. The mark is for the link, not for writing the three labels.

Which science topics lose the most marks on phrasing?

The ones where two ideas sit next to each other and pupils swap them: heat and temperature, evaporation and condensation, breathing and respiration, series and parallel, pollination and fertilisation. The content is usually in the P5 and P6 themes. A child who can recite the definition and still swaps the pair needs sentence practice, not another content pass.

Can parents mark open-ended science at home?

Parents can check whether the sentence answers the command word and names the concept. They often cannot tell a near-miss from an accepted answer, because the acceptable wording is settled at SEAB’s standardisation meeting and is wider than a single keyword. That is the usual reason families ask for a science tutor in P5 or P6.

Sources

Channel NewsAsia, “We want to honour our students’ responses: Chief marker lifts veil on PSLE marking process.” The PSLE Science chief marker describes standardisation at SEAB, and says the scheme focuses on conceptual understanding. A keyword used outside the concept does not secure the mark. Accessed 13 October 2026. https://www.channelnewsasia.com/cna-insider/psle-marking-process-exam-tips-science-chief-marker-students-4226016
Singapore Examinations and Assessment Board, PSLE. Science is examined on the primary science syllabus. Confirm the current booklet structure and duration on the syllabus for the year of the exam. Accessed 13 October 2026. https://www.seab.gov.sg/psle/